This invention is directed to a foil termination structure for an extended foil capacitor and a method for making the termination. The capacitor is an extended foil wound capacitor, and the method comprises the electron beam welding of the connector straps to the capacitor foil.
Foil capacitors are produced by winding two separate conductive foil layers insulated from each other. These foil layers must be electrically connected to terminals to electrically utilize the capacitor. In extended foil construction, the foil windings extend past opposite ends of the insulating layers to provide for connection. Connector straps are used in some such constructions. In the past, such connector straps have been attached to the foil layers by flame spraying of an electrically conductive bonding material, but such raises problems. Similarly, aluminum or tin-lead soldering of the foil to the connector has been tried, but both of these methods have a great potential for particulate contamination. The soldering requires corrosive flux which presents problems of cleaning and contamination, and the heat required tends to damage the capacitor insulation. Accordingly, to maximize performance and reliability, new methods are required.